Phase locking in a fiber laser array with varying path lengths

Phase locking has been demonstrated in fiber lasers coupled to a common resonator containing a spatial filter. The phase-locked mode is highly stable despite the phase variations in the individual elements caused by thermal and mechanical effects. The ability to maintain phase locking is attributed to a self-adjusting process, which can be found only in systems with a combination of high gain, long length, low Q, and broad gain bandwidth, all of which can be met in fiber laser arrays.